hospital story. Alex perez stat down with the siblings now suing the hospital. Here's the exclusive interview. Reporter: When sarah fudacz was wheeled in the operating room at toledo medical center, she thought she was given the gift of life. Instead, she awakened to a nightmare. Her ordeal began last mohr. She was diagnosed with chronic kidney fail your. To live, she would need a transplant. And doctors found a perfect match, her brother, paul. When he said yes, it was the most amazing feeling in my life. Reporter: That relief had turned to disbelief. I knew that something had gone wrong. I lifted up my shirt and realized I didn't have a an incision. Reporter: And the startling truth. A nurse had accidentally thrown away paul's donor kidney, apparently thinking it was medical waste. What made it clear to me, was seeing my sister walking around fine. And then, laying in bed, in a lot of pain. Somebody wasted part of my brother. Reporter: For three months, she was forced to return to dialysis. I just cried because i couldn't believe that I was back where I started, when I should have been healthy. I should have been recovering. Reporter: The hospital eventually found her another kidney in colorado and paid for fudacz's travel. But the fudacz family has filed a lawsuit. The university of toledo has issued a statement. We apologize. In court, the hospital is fighting back, asking a judge to dismiss parts of the lawsuits, leaving sarah fudacz to fight not only for her health, but she says, for justice. They threw away my life. They threw away something that meant so much to me. Reporter: For "good morning america," alex perez, abc news, chicago. Dr. Rich besser, back with us. The first question we all think, is how is this possible? They mark it up a million times. And asked me about it. When you talk about errors in medicine, there's errors that are called sometimes errors, no matter what you do, occasionally you're going to have a problem. You're going to have infection. Or you're going to have that outcome. This is what is called a never event. It should never happen. Because of the experience you have. There should be checklists, procedures that you follow, just like an airplane pilot follows. A kidney is not a small organ mistaken for medical waste. People did lose their job over this. It's clear they understood this should never happen. And it's not something people were going in for an organ donation or thinking about donating. What about the brother and sister. She had to wait several months for a match. When you donate an organ to a relative, it's a beautiful thing. You're putting yourself at slight risk. You can live fine with one kidney. But if something happens to that, you're at risk. He did that without any benefit to his sister. There's a benefit if you get an organ from a living donor. I don't know if the second kidney was from a living donor of someone who is deceased. There's better survival of a living donor. Both people here, at some risk. It's a sad story. But 17,000 kidney transplants a year. Never happens. Thank you so much.

This transcript has been automatically generated and may not be 100% accurate.